There is an extensive literature related to preparation of distilled spirits from agave. For example, a detailed description of the preparation of tequila from agave cactus is provided in Tequila Processing and Flavor, Pedro A. Vazquez-Landaverde and Miriam G. Rodriguez-Olvera, Centro de Investigación en Ciencia Aplicada y Tecnologfa Avanzada del Instituto Politécnico Nacional Unidad Querretaro, Cerro Blanco 141 Colinas del Cimatario, Queretaro, Qro., Mexico 76090; 2012 American Chemical Society; on the World Wide Web at //pubs.acs.org, Publication Date (Web): Jul. 16, 2012| doi: 10.1021/bk-2012-1104.ch015 In Flavor Chemistry of Wine and Other Alcoholic Beverages; Qian, M., et al.; ACS Symposium Series; American Chemical Society: Washington, D C, 2012, the disclosure of which is incorporated herein by reference for its description of treatment of the agave starting materials, fermentation, distillation and aging. Briefly, stems of the agave cactus are heated to hydrolyze complex sugars and shredded and crushed to release a syrup. The syrup is then diluted with water to provide a suitable dilution for inoculation with yeast. After fermenting, the fermentation culture is distilled to obtain a distillate. The distillate is sold as various brands of tequila of which there are many. The distillate, however, may be aged before packaging and selling.
The specific description set forth in the above-referenced source is as follows:
The mature agave stripped of leaves (referred to as the “pifia”) is cut in halves, quarters, or more, in order to make it easier for oven (48 h) or autoclave (12 h) baking at 106-116° C. This thermal treatment has the objective of hydrolyzing complex sugars like inulin and starch, to obtain glucose and fructose for an easier fermentation. Sugars result mainly in ethanol formation, many other compounds arise from the fermentation of this substrate. Resulting from the thermal treatment of the pifias, compounds are formed, mainly Maillard-related such as furans, pyrans, aldehydes, nitrogen and sulfur compounds. The most abundant Maillard compounds are methyl-2-furoate, 2,3-dihydroxy-3,5-dihydro-6-methyl-4(H)-pyran-4-one and 5-hydroxymethylfurfural. Pyrazines are also an important group of chemical compounds derived from Maillard reactions. Most abundant pyrazines found are 2,5-dimethylpyrazine and trimethylpyrazine.
Other thermally-related breakdown products arise during the baking step. Free fatty acids of short- and long-carbon chain have been found in baked pifias probably due to hydrolysis of acylglycerols, β-cyclocitral and β-damascenone are likely degradation products of carotenoids, while 4-methyl-5-(2-hydroxyethyl)-thiazole is a breakdown product of the amino acid thiamine Phenols like p-cresol and 4-ethyl phenol are a breakdown product of phenolic acids.
Once the pifias are baked, they are taken to a shredding mill and a crusher where they release all the syrup containing high concentration of sugars and the majority of the compounds. The resulting agave mash is often washed off in order to improve sugar extraction.
There is no doubt that fermentation is the most important and complicated stage of agave processing. 100% agave or mixto syrups are diluted with water to reach 12-14° BRIX (80-100 g/L of sugar). Fermentation takes place in thermostatized tanks at 30° C., although some processes are carried out at room temperature, which could be variable depending on the season of the year. Fermentation depends entirely of the metabolism of yeasts and in less extent of lactic and acetic acid bacteria. Many strains of yeasts have been found in agave musts, being Saccharomyces cerevisiae and Kloeckera africana the most important ones. Yeasts metabolize carbohydrates, amino acids, fatty acids and other organic compounds, transforming them into ethanol, glycerol, carbon dioxide, and in a less extent into aldehydes, ketones, higher alcohols, organic acids and esters, which are called “fermentation by-products” or “congeners.” Higher alcohols, also called “fusel alcohols” because of their malty and burnt flavor, are formed by degradation of amino acids via keto acids (2-oxo acids). The most important ones are 1-propanol, 2-methyl-1-propanol, 2-methyl-butanol, 3-methyl-butanol, and 2-phenylethanol, the later having a rose-like aroma. Synthesis of fatty acids inside the yeast cell forms mainly saturated straight-chain fatty acids with an even number of 4 to 18 carbon atoms, and the appearance of low levels of fatty acids with odd carbon numbers and unsaturations depends on the fermentation conditions. Fatty acids can combine with alcohols to form esters.
Fermentation proceeds for 18 to 24 hours at 30 to 35° C. A processing temperature of 35° C. produces more volatile compounds than 30° C. Also, it has been observed that supplementation with a nitrogen source changes compound formation by yeasts during fermentation, although the effect is different depending on the nitrogen source used. By adding a mixture of 20 amino acids, Kloeckera africana strain K1 is able to produce and tolerate higher ethanol concentrations, while the production of some esters, alcohols, acetaldehyde and α-terpineol is increased. When using Saccharomyces cerevisiae in a must supplemented with sodium sulfate and amino acids, the concentration of amyl alcohols and isobutanol decrease, while propanol an acetaldehyde increase.
Once the fermentation is over, and alcohol content reaches about 15% v/v, it is time for distillation. The fermented mash is heated in copper or stainless steel kettles at 78-80° C. so evaporation of alcohol is achieved. Vapors are condensed in cooled coils and a distillate is collected. First distillate reaches an alcohol concentration of ˜25% v/v, and needs a second distillation also called rectification, in order to reach ˜55% v/v of ethanol. The liquid is then adjusted with water to 38-40% v/v alcohol. Since the majority of compounds are volatile, they are evaporated along with ethanol during distillation. It is possible to separate different fractions of volatiles or “cuts” during distillation. The head cut contains highly volatile compounds like acetaldehyde and ethyl acetate, whereas the tail cut has higher boiling point chemicals such as ethyl esters of long-chained fatty acids. Since the both fractions are undesirable, they can be separated from the heart cut. Methanol is obtained in the tail, despite its low boiling point. Ethyl lactate, acetic acid and furfural are also distilled in the tail fraction. Isobutyl and isoamyl alcohols behave as head products, n-propyl alcohol is found in the heart, and phenethyl alcohol exhibits a tail product behavior.
Heat plays an important role on compound generation during distillation. Because of this it is possible that some breakdown reactions take place, and formation of aldehydes, ketones, furans, sulfur compounds, pyrazines, and phenols occur.
The rectified distillate adjusted with water to 40% ethanol content may be aged for two months to three years in oak casks. Aldehydes evaporate and/or form acetals. By aging in wooden casks, volatile compounds such as vanillin, guaiacol, eugenol, cresol and other phenolics migrate from the wood to the distillate, up-rounding the flavor. Ethyl esters are not only formed during fermentation, but also during aging. It has been reported that esters may be formed subsequently during the aging process by esterification of fatty acids with ethanol at high concentrations.
The foregoing description is as found in the above-referenced document. A wide variety and multiplicity of compounds that are components of agave extracts and/or spirits prepared from them have been identified; however, to applicant's knowledge, it has not been understood that the beverages commonly marketed as tequila or others derived from agave contain MAO inhibition activity. As it is known that MAO inhibitors can be used as mood elevators, antidepressants and treatments for various other diseases, including Parkinson's disease, the non-alcoholic “energy drink” that is comprised of the alcohol-free components of these beverages is useful in these contexts.